Electron-Microscopic Image of an Edge Dislocation Perpendicular to the Crystal Surface

Abstract

The dynamical theory of electron diffraction is extended to interpret the contrast of the electron-microscopic images of an edge dislocation perpendicular to the crystal surface. The wave function of electron passed through a region of a crystal is derived from an approximation that the electron wave travels in the region as if the neighbouring regions have the same lattice as that of the region concerned. The lattice distortion around the dislocation is replaced by a parameter which expresses the condition of diffraction. The intensity distribution of electron waves around the edge dislocation is calculated for the case of crystal image, lattice fringes and moiré fringes.
The calculated images are compared with the electron-micrographs and the coincidence between them is satisfactory.